1. Field of the Invention
This invention relates generally to semiconductor manufacturing, and, more particularly, to a method and apparatus for indexing manufacturing data for improving efficiency of data storage and/or data retrieval.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today's manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital and, therefore, require a number of inputs that are generally fine-tuned to maintaining proper manufacturing control. The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
Generally, a set of processing steps is performed across a group of semiconductor wafers, sometimes referred to as a lot. For example, a process layer that may be composed of a variety of different materials may be formed across a semiconductor wafer. Thereafter, a patterned layer of photoresist may be formed across the process layer using known photolithography techniques. Typically, an etch process is then performed across the process layer using a patterned layer of photoresist as a mask. This etching process results in the formation of various features or objects in the process layer. Such features may be used as, for example, a gate electrode structure for transistors. Many times, trench isolation structures are also formed across the substrate of the semiconductor wafer to isolate electrical areas across a semiconductor wafer. One example of an isolation structure that can be used is a shallow trench isolation (STI) structure.
The manufacturing tools within a semiconductor manufacturing facility typically communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface to which a manufacturing network is connected, thereby facilitating communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script, which can be a software program that automatically retrieves the data needed to execute a specific manufacturing process.
FIG. 1 illustrates a typical semiconductor wafer 105. The semiconductor wafer 105 typically includes a plurality of individual semiconductor die 103 arranged in a grid 150. Using known photolithography processes and equipment, a patterned layer of photoresist may be formed across one or more process layers that are to be patterned. As part of the photolithography process, an exposure process is typically performed by a stepper on single or multiple die 103 locations at a time, depending on the specific photomask employed. The patterned photoresist layer can be used as a mask during etching processes, wet or dry, performed on the underlying layer or layers of material, e.g., a layer of polysilicon, metal or insulating material, to transfer the desired pattern to the underlying layer. The patterned layer of photoresist is comprised of a plurality of features, e.g., line-type features or opening-type features that are to be replicated in an underlying process layer.
When processing wafers, a large amount of metrology data and/or test data relating to various portions of a processed wafer is acquired. Data relating to metrology analysis or the testing of portions of the wafer are stored into large databases. These databases may accumulate large amounts of data that has to be processed and organized for later retrieval. Often, upon acquiring significant amount of manufacturing data, prohibitively large amounts of data may be available for storage and retrieval.
Referring now to FIG. 2, a flowchart depiction of a typical prior art process flow is illustrated. A manufacturing system may process a batch of wafers in a lot (block 210). Manufacturing data relating to portions of the wafers e.g., metrology data or testing results, is generally acquired (block 220). For example, data relating to various bits in a memory array may be acquired, wherein the data may be indicative of whether a particular bit in a memory array is operational or at failure. The system may then store large bit maps of failure data (block 230). Large databases are generally used to store the data relating to the bitmap or other types of failures. The manufacturing system may then analyze the stored data to perform corrections for subsequent processes of semiconductor wafers 105 (block 240).
Among the problems associated with the current methodology includes the requirement of storing large amounts of data, which prompts the usage of considerable computing resources and time. The exact coordinates of failing bits in a memory device array or failing regions in a die is generally important in performing failure analysis. The coordinates of the failing bits or die regions are also important in performing yield analysis during manufacturing. Therefore, failure data relating to each of the failed bits or die regions are meticulously stored and organized for later retrieval. Therefore, even for a relatively small scale manufacturing line, the storage and organization of failing bits may become a massive task. Retrieving the data may also require significant computing resources and processing time. Therefore, corrections of subsequent processes may be delayed by the time period required for retrieving and analyzing data stored in massive databases. Additionally, considerable resources are used in the manufacturing system to store, organize, and track the failure data.
The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.